Two-way communications headsets are in common use in many types of vehicles and with various large pieces of machinery, especially vehicles and machinery that create a high noise environment during operation such that necessary two-way communications with the driver, operator or pilot would be impaired without such headsets. Examples of such noisy environments include airplane cockpits, drivers compartments in commercial trucks and tractors, operator cabins in cranes and tunnel boring machines, and crew compartments in tanks and other military vehicles. It is commonplace for such vehicles and machinery to incorporate an intercom system providing one or more connection points to which such headsets are coupled. Such intercoms typically cooperate with multiple ones of such headsets to enable personnel within or in the immediate vicinity of such vehicles to communicate with each other, and such intercoms typically incorporate long-range wireless transceivers enabling personnel to use such headsets in communicating with other personnel at a distance.
It has recently become increasingly desired to further enable such headsets to be coupled to portable audio devices that personnel may carry with them, in addition to being able to be coupled to an intercom system of a vehicle or large piece of machinery. Therefore, it has become desirable to enable the simultaneous coupling of a headset to both an intercom system and a personal audio device in a manner that provides a high degree of ease of use of such a combination, and avoids electrical incompatibility problems due to changes in a headset's operating state between being coupled to and uncoupled from an intercom system.